A changeover valve that switches an exhaust flow path by use of a valve body is mounted to an exhaust system of an internal combustion engine. This changeover valve is employed by being attached at an opening portion of an exhaust pipe that opens inside a muffler and so on. In this changeover valve, the valve body capable of closing the opening portion is rotatably supported by a supporting member attached to the exhaust pipe and is biased in a valve closing direction by a coil spring. Therefore, because the pressure of an exhaust gas at an upstream side of the changeover valve is low when the rotational speed of the internal combustion engine is low, the opening portion turns to a valve closed state in which the opening portion is closed by the valve body, and the exhaust sound is reduced. Meanwhile, as the rotational speed of the internal combustion engine goes up, the pressure of the exhaust gas at the upstream side of the changeover valve becomes high. Accordingly, the valve body is separated from the opening portion and the opening portion turns to a valve open state in which the opening portion is released from the valve body, so that pressure loss is reduced.
This changeover valve includes a configuration in which the valve body abuts the supporting member and closes the opening portion of the exhaust pipe. Further, a wire mesh is mounted on the supporting member at an area in which the valve body comes in contact with the supporting member at the time of valve-closing. This wire mesh is held between the valve body and the supporting member at the time of valve-closing and fills in a gap between the valve body and the supporting member. Therefore, exhaust sound leakage through the gap between the valve body and the supporting member is inhibited at the time of valve-closing. Further, the wire mesh functions as a cushion to receive the valve body at the time of valve-closing. Therefore, in a changeover valve having this wire mesh, an occurrence of the hammering sound generated when the valve body contacts the supporting member quickly is inhibited at the time of valve-closing.
Meanwhile, for example, Patent Document 1 discloses a changeover valve not having a wire mesh. This changeover valve has a configuration in which a valve body has a protrusion and the protrusion abuts on a planar surface provided at a supporting member at the time of valve-closing.